Film forming mechanism



E. M. KRATZ FILM FORMING MECHANISM Filed June 29,

2 Sheets-Sheet l April 28, E M ATZ FILM FORMING MECHANISM Filed June 29, 1933 2 Sheets-Sheet 2 500mm? M. KAA TZ.

Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE FILM FORMING IVIECHANISM Application June 29, 1933, Serial No. 678,308

8 Claims.

This invention relates to improvements in film forming apparatus and includes an improved method of forming films on a carrier belt.

More specifically, this invention relates to apparatus for forming uniform, smooth films and applying the same onto a traveling carrier belt.

The formation of smooth and uniform sheets of a transparent nature can be brought about by setting a liquid material with another liquid material, forming a film of the materials and casting them onto a traveling belt While they are still plastic. Because of the rapid setting action of the liquid ingredients it is necessary that they be mixed together not more than a few minutes before being cast in film form onto a carrier belt. For example, in the formation of thin transparent sheets, composed of casein which has been hardened with formaldehyde or similar hardening agents, the hardening or setting action occurs too quickly to permit the mixing of a batch of the active ingredients for casting in films onto the belt. As a result, it is essential that the active ingredients forming the sheets be mixed together to a uniform mixture which is quickly formed into a film and cast onto the carrier belt. If the mixture is allowed to stand more than a few minutes it will set into a viscous jell that cannot be formed into a sheet.

In the application filed by myself and Herman Heckel, Serial 630,406, filed Aug. 25, 1932, there is described a film forming apparatus for manufacturing transparent sheets in which casein and formaldehyde or other hardening agents are mixed together in the proper proportions in a proportioning pump and immediately fed through tubes to a coating roll. A doctor bar is carefully adjusted to a previously determined distance away from the coating roll so as to remove excess material from the roll. This doctor or scraper bar therefore regulates the thickness of the film. After passing under the doctor bar, the casein material on the coating roll contacts a traveling carrier belt and is deposited thereon.

I have now provided improvements in the film forming mechanism described in the copending application Serial No. 630,406.

In accordance with this invention, the reacting ingredients to form the transparent sheets in proper admixed proportions are fed to a rotating coating roll. The thickness of the film on the coating roll is regulated by a reverse coating roll rotating in the same direction as the coating roll and in adjustable spaced relation therefrom. Since therolls rotate in the same direction a scraping and smoothing action exists between them. As the material picked up by the coating roll passes between the nip of the reverse roll and the coating roll, it is formed into a smooth film which is picked up by the carrier belt. Improved scraping devices are provided to maintain the coating roll and the reverse roll in a clean and smooth condition.

It is therefore an object of this invention to provide a film forming mechanism for manufacturing transparent sheet materials.

Another object of this invention is to: provide an apparatus for casting films onto a carrier belt in such a manner that an even, smooth and uniform sheet results.

Another object of this invention is to provide a process for forming transparent sheet material from initial ingredients which rapidly react to form a solid mass.

Another object of this invention is to provide film forming apparatus for transparent sheet material manufacture which is capable of accurate adjustment and may be used continuously over long intervals of time without necessity of readjustment.

Other and further objects of this invention will be apparent to those skilled in the art from this specification and the hereinafter described drawings which form part of this description.

On the drawings:

Figure 1 is a side elevational view of the film forming mechanism showing the driving mechanism in dotted lines.

Figure 2 is a broken front elevational view of the film forming apparatus.

Figure 3 is an enlarged sectional view taken substantially along the line IIIIII of Figure 1.

Figure 4 is an enlarged sectional view taken along the line IV-IV of Figure 2.

As shown on the drawings:

In Figures 1, 2 and 4, the reference numerals l9 indicate vertical supporting means or frame structure for the film forming mechanism. Horizontal supporting arms ll having flat top surfaces I2 provided with dovetailed grooves l3 are secured to the vertical supports l0.

Bearing carriages [4 for a coating roll 20 are slidable on the surfaces l2 of the supporting arms I l and have dovetails for fitting into the grooves I3 in the surfaces l2. The carriages l4 carry bearing caps Ma for the roll 20.

The carriages l4 support members l5 which are provided with fiat inclined surfaces l6 for receiving bearing carriages H for a reverse coat ing roll l8. The members I 5 are bolted onto the carriages M by means of bolts l9 (Fig. 2). Carriages ll support bearing caps Ila for the roll I8.

The bearing carriages M for the coating roll 20 are moved along the arms H by means of screws 2| rotatably mounted in bosses 22 integral with the supports ll. Hand wheels 23 are provided to manually operate the screws 2|.

The bearing carriages I! for the reverse coating roll l8 moves along the dovetail groove track l6 by means of screws 25 which are rotatably secured in bosses 26 integral with the supporting structure I5. The screws are actuated by hand wheels 21.

A roll 36, which is preferably rubber covered, is provided for directing a carrier belt 3I against the coating roll 28. The roll 39 is rotatably mounted in bearing supports 32 which are slidable in tracks 33 on the vertical beams I0. Screws 34 are provided for moving the roll along the tracks 32. Collars 35 (Fig. 1) are secured to the beams II] in screw thread relation with the screws 34 so that a rotation of the screws 34 will slide the roll 30 relative to the beams I0. Lock nuts 36 and 31 (Fig. 1) may be provided to hold the bearing supports 32 in adjusted position.

From the above description, it is evident that the rubber covered roll is vertically adjustable along the supporting means ID. The coating roll 20 is horizontally adjusted along the horizontal arm II and the reverse coating roll I8 is adjustable on an inclined plane along the supporting member I5. The three rolls may therefore be brought into cooperative relation and adjusted at will to meet whatever changes are necessary. The micrometer adjustment made possible by the use of fine,threaded screws provides minute control of the three rolls at all times.

As shown in Fig. 4, an angle member 39 is rotatable in a U-shaped saddle support 4|. A trough plate 46 is secured to the member 39 to scrape against the coating roll 20. End plates 42 are provided to form the ends of the trough. Weights 43 may be adjusted along lever arms 44 secured to the member 39 at right angles to the plate for adjusting the pressure of the end of the plate against the coating roll 20.

A plurality of tubes or pipes 45 are secured at their ends in the plate 40 near the lower edge thereof for supplying the film forming material in properly admixed proportion to the trough. A small pond of film forming material 46 (Fig. 4) is therefore maintained in the lower part of the trough formed by the plates 48, 42 and the coating roll 20. This film forming material in the pond is immediately picked up by the roll 20 and formed thereon in a thin film 48 (Fig. 4) The rolls I8 and 20 both rotate in a clockwise direction, (viewed as in Fig. 4) so that their adjacent surfaces move in opposite directions and the excess film forming material is therefore removed and the outside of the film 48 is provided with a smooth surface.

An angle member 49 is rotatably mounted in a U-shaped saddle support 50 for securing a scraper plate 5I in operative position against the reverse coater roll I8. Lever arms 52 are provided for supporting weights 53 which are slidably adjustable thereon. The scraper plate 5| is thus held against the reverse coater roll I8 to remove film forming material therefrom. The pressure of the scraper against the roll may be adjusted by varying the position of the weights 53 along the lever arms 52.

Angle members and BI rotatably mounted from supports 62 are provided to hold scraper plates 63 and 64. Lever arms 65 and 66 are secured to the angle members 60 and GI respectively. The lever arms 65 and 66 are connected to spring tensioning means 61 and. 68 for adjusting the plates 63 and 64 against the fountain roll 20 to remove any film material which may remain thereon after the film has been transferred to the carrier belt 3I. Wing nuts 69 and 18 are provided to regulate the tension of the scraper plates 63 and 64 against the roll 28. While two scraper plates 63 and 64 are shown in Fig. 4, it is to be understood that in some instances a single plate 63 may be sufficient as shown in Fig. 1.

As shown in Fig. 3, the reverse coater roll I8 is preferably provided with a central bore or opening 'II to receive heating or cooling fluid from a pipe 72. The roll I8 may thus be maintained at a constant temperature and any expansion or contraction of the roll caused by temperature changes is therefore eliminated. The relative positioning of the rolls I8 and. 28 is very important, as the distance between these rolls determines the thickness of the film being formed. These rolls are accurately ground and may be provided with stainless steel jacketed or chromium plated surfaces if desired. A drain line I3 is provided at the other end of the roll I8 as shown in Fig. 2 to remove the fluid introduced through feed pipe I2.

The rolls I8 and 20 are driven in the same direction by separate chain drive means from the same source of power. A chain 8!] drives the sprocket gear 8I, which is mounted on a shaft 82 in the vertical supporting members II]. The shaft 82 runs across the width of the machine and is provided at its opposite end with a pulley 83 for driving a belt 84, which, in turn, drives a large pulley 85 secured to the shaft of the reverse coating roll I8. An idler gear 86 is preferably mounted on the supporting member Ill adjacent the gear 8| to take up slack in the chain. Likewise, an idler pulley (not shown) may be provided to take up slack in the belt 84 due to stretching or to adjustment of the roll I8.

The coating roll 20 is driven by a chain drive 81 which rotates a sprocket gear 88 secured to the shaft 89 of the roll 20. The rolls I8 and 20 are therefore driven in the same direction. However, since their adjacent surfaces travel in opposite directions, the roll I8 is called a reverse coater roll and removes excess film forming material from the fountain roll 20.

The rubber covered roll 39 is driven by the carrier belt 3I which, in turn, is preferably driven by contact with a suction roll (not shown).

The operation of the film forming device may be briefly described as follows. The rolls I8, 20 and 30 are rotated in a clockwise direction (as viewed in Fig. 4), being driven from a suitable power source. Proper contact of the coating roll 20 with the carrier belt 3I, as it travels over the rubber roll 30, is made by manual control of the adjusting screws 2I. The adjusting screws 25 are set to hold the reverse coater roll I8 in the proper spaced relation from the coating roll 20, so that a sheet of the desired thickness will be formed.

The weights 43 are set to hold the trough member 48 tightly against the coating roll 20. The weights 53 are likewise set to hold the scraper plate 5I tightly against the reverse coater roll I8 and the tensioning devices 61 and 68 are set to hold the scraper plates 63 and 64 against the I coating roll 20.

[8 and 20 whereupon it is formed to a uniform thickness and provided with a finished outside surface.

The scraper plate removes any material that is retained on the roll l8 so that the smooth finished peripheral surface of the roll I8 is always presented to the film 48. The roll I8 is preferably chromium plated and highly polished. It may be kept at a uniform, warm temperature by passing hot water through the chamber H provided through its interior.

The film 48, after advancing through the nip between the rolls I8 and 20, contacts the carrier belt 3| traveling in a reverse direction thereto. The carrier belt strips the film from the coating roll and as the roll rotates into contact with the scraper plate 64, any of the film forming material which may have had adhered to the roll is removed by the scraper plate. The coating roll is scraped again by a second scraper plate for removing the last traces of foreign material that may have adhered thereto. The surface of the roll next contacts with the pond of film forming material in the trough 40 and picks up a fresh layer of material therefrom.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

Having now described my invention, what I claim is:

1. In a film forming apparatus, in combination, a coating roll, a reverse coating roll, means for driving the reverse coating roll in the same direction as the coating roll, a traveling carrier belt, a rubber covered roll for guiding said carrier belt against said coating roll, means for adjusting said coating roll horizontally, means for adjusting said reverse coating roll along an inclined plane relative to said coating roll, and means for vertically adjusting said rubber covered roll, said means cooperating to provide positive control of formation and thickness of the film.

2. A film forming apparatus for transparent sheet material comprising, in combination with a coating roll, a plate adapted to scrape against said coating roll at an inclined angle thereto, end plates abutting said inclined plate to form a trough enclosure, means for adjusting the scraping action of the plate against the roll, a plurality of feed means for supplying the trough with film forming material whereby a pond of said material is formed against the coating roll and a film of the material is picked up by the coating roll, a cooperative roll in adjustable spaced relation to said coating roll, means for driving said cooperative roll in the same direction as said coating roll whereby excess film forming material is removed from the coating roll as the film thereon passes between the nip of the two rolls and means for transferring the film from the coating roll.

3. Film forming apparatus comprising, in combination, vertical and horizontal supporting members, bearing carriage means slidable on said horizontal supporting members, a coating roll rotatably mounted on said carriage means, bearing supporting means slidably mounted on said first carriage means, a reverse coating roll rotatably mounted on said bearing supporting means, means for horizontally adjusting said coating roll on said horizontal support and means for adjusting said reverse coating roll along an inclined plane in spaced relation from said coating roll.

4-. Film forming apparatus comprising, in combination with supporting means, supporting carriages slidably mounted on said supporting means, bearing means on said slidable carriages, a coating roll rotatably mounted in said bearing means, bearing carriages slidably mounted along inclined planes on said carriage supporting means, .a reverse coating roll rotatably mounted in said bearing carriages, means for sliding said supporting carriages horizontally and means for moving said bearing carriages along said inclined planes, said means cooperating to vary the relative position of the rolls.

5. In an apparatus for manufacturing transparent sheet material, in combination, a coating roll, means for supplying said coating roll with film forming material, a reverse coating roll in superimposed relation to said coating roll, a resilient roll, a carrier belt trained around said resilient roll, means for moving said resilient roll to contact the belt therearound with the coating roll at a point after the coating roll has advanced under the reverse roll, means for moving the coating roll in a horizontal plane and means for moving the reverse roll along an inclined plane whereby the distance of travel of the film on the coating roll before advancing under the reverse roll and the space between said rolls can be readily adjusted.

6. A film forming apparatus comprising, in combination, a trough, a fountain roll rotatable through said trough, a reverse coating roll above said trough in adjustable spaced relation from the periphery of the fountain roll, a resilient roller above said fountain roll, a casting belt trained around said resilient roller in contact with said fountain roll, means for rotating said fountain roll and means for rotating said resilient roller to advance the casting belt in a direction opposite to the direction in which the surface of the fountain roll is rotated.

7. A film forming mechanism comprising, in combination, a trough for containing a film forming solution, a fountain roll rotatable through said trough for picking up a film of said solution on its periphery, a reverse coating roll in adjustable spaced relation from the periphery of said roller to gauge the thickness of the film thereon, a casting belt adapted to pick up the gauged film on said fountain roll and means for advancing said belt in a surface direction opposite to the direction in which the periphery of the fountain roll is rotating so that the film thereon is wiped off by the belt.

8. The process of making transparent sheet material which comprises picking up a film of sheet forming solution on a smooth rotating surface, wiping said film against a reverse rotating surface to uniformly gauge the film, contacting the gauged film with a carrier belt advancing in a direction opposite to the direction in which the film is traveling to wipe the film from the rotating surface onto the belt, allowing the film to dry on the belt and stripping the resulting sheet from the belt.

EDOUARD M. KRATZ. 

